An LCD has the advantages of portability, low power consumption, and low radiation, and has been widely used in various portable information products such as notebooks, personal digital assistants (PDAs), video cameras and the like. Furthermore, the LCD is considered by many to have the potential to completely replace CRT (cathode ray tube) monitors and televisions. An LCD generally includes a liquid crystal panel, a driving circuit for driving the liquid crystal panel, and a backlight module for illuminating the liquid crystal panel.
Referring to FIG. 4, a typical backlight module 100 includes a light guide plate 110 having a light incident surface 111, a light source assembly 114, and a frame 116 for accommodating the light guide plate 110 and the light source assembly 114.
The light source assembly 114 includes a light source 117, a pair of fixing blocks 119, and a light reflector 118. The light source 117 can be a cold cathode fluorescent lamp (CCFL), and is positioned adjacent to the light incident surface 111 of the light guide plate 110. High and low voltages are applied to the two ends of the CCFL so that the CCFL lights up. The light reflector 118 has a generally U-shaped cross-section, and thus can accommodate the light source 117. The fixing blocks 119 are configured to fix the light source 117 to the light reflector 118. The light reflector 118 can reflect light beams toward the light guide plate 110, thereby increasing light utilization of the backlight module 100.
Generally, the brightness of the two ends of the CCFL is lower than the brightness of a middle portion of the CCFL. Thus the light guide plate 110 receives non-uniform incident light beams from the light source assembly 114, and the brightness of light output by the backlight module 100 may also be non-uniform. Accordingly, a liquid crystal display using the backlight module 100 may have impaired display quality.
Alternatively, the light source 117 can instead be a plurality of light emitting diodes (LEDs). In general, lower powered LEDs are used, in order to limit the amount of heat produced and limit power consumption. Therefore the brightness of this kind of backlight module 100 may be too low.
What is needed, therefore, is a new backlight module that can overcome the above-described deficiencies. What is also needed is an LCD using such backlight module.